The present invention relates generally to interface devices for allowing humans to interface with computer systems, and more particularly to mechanical computer interface devices that allow the user to provide input to computer systems and provide force feedback to the user.
Computer systems are used extensively in many different industries to implement many applications, such as word processing, data management, simulations, games, and other tasks. A computer system typically displays a visual environment to a user on a display screen or other visual output device. Users can interact with the displayed environment to perform functions on the computer, play a game, experience a simulation or "virtual reality" environment, use a computer aided design (CAD) system, browse the World Wide Web, or otherwise influence events or images depicted on the screen.
One visual environment that is particularly common is a graphical user interface (GUI) GUI's present visual images which describe various graphical metaphors of a program or operating system implemented on the computer. Common GUI's include the Windows.RTM. operating system from Microsoft Corporation and the MacOS operating system from Apple Computer, Inc. These interfaces allows a user to graphically select and manipulate functions of the operating system and application programs by using an input interface device. The user typically moves a user-controlled graphical object, such as a cursor or pointer, across a computer screen and onto other displayed graphical objects or predefined screen regions, and then inputs a command to execute a given selection or operation. The objects or regions ("targets") can include, for example, icons, windows, pull-down menus, buttons, and scroll bars. Most GUI's are currently 2-dimensional as displayed on a computer screen; however, three dimensional (3-D) GUI's that present simulated 3-D environments on a 2-D screen can also be provided.
Other programs or environments that may provide user-controlled graphical objects such as a cursor include browsers and other programs displaying graphical "web pages" or other environments offered on the World Wide Web of the Internet, CAD programs, video games, virtual reality simulations, etc. In some graphical computer environments, the user may provide input to control a 3-D "view" of the graphical environment, i.e., the user-controlled graphical "object" can be considered the view displayed on the video screen. The user can manipulate the interface device to move the view, as if moving a camera through which the user is looking. This type of graphical manipulation is common in CAD or 3-D virtual reality applications.
The user interaction with and manipulation of the computer environment is achieved using any of a variety of types of human-computer interface devices that are connected to the computer system controlling the displayed environment. In most systems, the computer updates the environment in response to the user's manipulation of a user-manipulatable physical object ("user object") that is included in the interface device, such as a mouse, joystick, trackball, etc. The computer provides visual and audio feedback to the user utilizing the display screen and, typically, audio speakers.
Another mode of feedback recently introduced to the consumer home market is force feedback, which provide the user with sensory "haptic" (feel) information about an environment. Most of the consumer force feedback devices are joysticks which include motors to provide the forces to the joystick and to the user. Current force feedback joystick devices may allow realistic and effective forces to be transmitted to a user; however, the standard joystick device is well-suited for such uses as controlling an aircraft or other simulated vehicle in a simulation or game, first-person perspective virtual reality applications, or other rate-control tasks and is not well suited to position control tasks such as controlling a pointer or cursor in a graphical user interface. Other types of controllers, such a mouse, trackball, stylus and tablet, "touch point" keyboard pointers, and finger pads are commonly provided for cursor position control tasks since they are adept at accurately controlling the position of a graphical object in two dimensions. Herein, "position control" refers to a direct mapping of the position of the user object with a user-controlled graphical object, such as controlling a cursor in a GUI, while "rate control" refers to an indirect or abstract mapping of user object to graphical object, such as scrolling text in a window, zooming to a larger view in a window of a GUI, or controlling velocity of a simulated vehicle.
A problem with the currently-available position control interface devices is that none of them offer realistic force feedback. A mouse is not easily provided with force feedback since the mouse must be moved in a planar workspace and is not easily connected to actuators which provide the force feedback. Controllers as trackballs and tablets are even less well suited for force feedback than a mouse controller due to their free-floating movement. A joystick, in contrast, is typically connected to an immobile base which can include large actuators needed to provide realistic forces on the joystick. A mouse can be coupled to actuators from a side linkage, but a compact, low cost, and conveniently-positioned mechanism allowing free movement of a mouse as well as providing realistic force feedback for the mouse has not been available in the consumer market.